CVE-2021-36551Public exploitNetwork attack vector

Victim-context script execution via calendar description link

Published Oct 28, 2021 · Updated Aug 4, 2024

Stored XSS in Tiki Wiki CMS Groupware 21.4 allows remote authenticated users to execute script via a crafted calendar event. The Add Event workflow stores an encoded JavaScript anchor in the Description field and renders it as an executable link in event details. An authenticated user must create the event, and a victim must open its details and click the injected link, enabling script execution in the victim's Tiki origin.

CVSS severity5.4
Medium
EPSS probability0.50%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Tiki Wiki CMS Groupware 21.4 allows remote authenticated users to execute script via a crafted calendar event. The Add Event workflow stores an encoded JavaScript anchor in the Description field and renders it as an executable link in event details. An authenticated user must create the event, and a victim must open its details and click the injected link, enabling script execution in the victim's Tiki origin.

The record

CVE
CVE-2021-36551
Published
Oct 28, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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